Definition of Glaucoma, angle-closure

Glaucoma, angle-closure: Increased pressure in
the front chamber (anterior
chamber) of the eye due to sudden (acute) or slowly
progressive (chronic)
blockage of the normal circulation of fluid within the eye.
The block takes
place at the angle of the anterior chamber formed by its
junction of the
cornea with the iris. This angle can be seen by simply
looking at someone's
eye from the side. Angle-closure glaucoma tends to affect
people born with a
narrow angle. People of Asian and Eskimo ancestry are at
higher risk of
developing it. Age and family history are risk factors. It
occurs in older
women more often than others.

When the pupil of the eye is wide open
(dilated), the iris is retracted and thickened and it block
the canal of
Schlemm, a key component of the drainage pathway for fluid
within the eye.
Blocking the drainage canal of Schlemm sends the pressure
within the eye up.
With acute angle-closure glaucoma, there is an abrupt
increase in
intraocular pressure (IOP) due to the buildup of aqueous
(fluid) in the eye.
The high pressure can damage the optic nerve (the nerve to
the eye) and lead
to blindness. The elevated pressure is best detected before
the appearance
of symptoms. That is why when the eyes are dilated in a
doctor's office for
a refraction, eye pressures are checked. When symptoms of
acute angle
glaucoma do develop, they include severe eye and facial
pain, nausea and
vomiting, decreased vision, blurred vision and seeing
haloes around light.
The eye in a far advanced case of angle closure glaucoma
appears red with a
steamy (clouded) cornea and a fixed (nonreactive) dilated
pupil. Acute
angle-closure glaucoma is an emergency because optic nerve
damage and vision
loss can occur within hours of the onset of the problem.

Administering
medications to lower the pressure within the eye is done
first. In the past,
a piece of the iris was then surgically removed in a
procedure called an
iridectomy to make a hole in the iris and create a channel
(other than the
canal of Schlemm) to permit the free flow of fluid. Today a
comparable
procedure can be done by laser to burn a small hole in the
iris to keep the
intraocular pressure within normal limits.

This condition
can be chronic
(progressing slowly or occurring persistently) or acute
(occurring
suddenly). Chronic angle-closure glaucoma, like the more
common type of
glaucoma (open-angle glaucoma), may cause vision damage
without symptoms.